81135556743 has 4 divisors (see below), whose sum is σ = 108180742328. Its totient is φ = 54090371160.

The previous prime is 81135556739. The next prime is 81135556757. The reversal of 81135556743 is 34765553118.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 81135556743 - 2² = 81135556739 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81135556692 and 81135556701.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81135556543) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13522592788 + ... + 13522592793.

It is an arithmetic number, because the mean of its divisors is an integer number (27045185582).

Almost surely, 2^81135556743 is an apocalyptic number.

81135556743 is a deficient number, since it is larger than the sum of its proper divisors (27045185585).

81135556743 is a wasteful number, since it uses less digits than its factorization.

81135556743 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27045185584.

The product of its digits is 1512000, while the sum is 48.

The spelling of 81135556743 in words is "eighty-one billion, one hundred thirty-five million, five hundred fifty-six thousand, seven hundred forty-three".